1. Field of the Invention
The present invention relates to an optical connector plug used for a connecting end of an optical fiber cable.
2. Prior Art
In the prior art, as an LC type plug to be mainly fitted into an adapter having an LC type opening as an optical connector plug, an LC type plug including: a cylindrical plug frame having a ferrule and a resilient member configured to bias the ferrule toward the front in the interior thereof; a cylindrical movable front housing surrounding the plug frame so as to be in sliding contact with an outside thereof; a light-shielding plate having a curved shape, fixed at one end portion thereof to an inner wall of the front housing, and configured to block light at a position in front of the ferrule; and the locking housing configured to be fitted from the rear of the plug frame is known as disclosed in JP-A-2011-13606.
With the LC type plug, the light-shielding plate blocks a laser from the ferrule to protect eyes or the like in a non-connected state with respect to the LC type adapter, and the light-shielding plate is extended from the curved shape to the straight shape by the front housing and the ferrule projects from an opening end portion of the front housing which is moved toward the rear in the connected state, so that the ferrule on the plug side and a ferrule of the adapter on the connection counterpart are connected.
However, as illustrated in FIGS. 9A and 9B, in an optical connector plug 15 of the prior art, the light-shielding plate is extended and opened to the straight shape by a rearward movement of a front housing 151, and the front housing 151 comes into contact with an opening of the LC type adapter of the connection counterpart and is forced to retract in a direction opposite to a direction of insertion.
A locking projection 153 is formed on a sidewall surface of the front housing 151 so as to come into contact with the opening of the LC type adapter and to be pushed rearward. However, a height of the locking projection needs to be set so as to match the shapes of the openings 12 and 14 of all the existing LC type adapters 11 and 13 as illustrated in FIGS. 10A to 10D, and FIGS. 11A to 11D, so that adequate setting conforming to the condition is difficult.
As illustrated in FIG. 11A to FIG. 11D, a clearance “c” for forming the locking projection is required, so that there are adapters having a large width in part of the opening. Therefore, there is a problem that an insertion and pulling force required for the LC type plug varies depending on the difference in shape of the opening of the adapter.
In addition, in order to provide the locking projection 153 formed on a sidewall of the front housing with a spring property when causing the same to retract inward at the time of fitting, a slit hole 152 is required. With the presence of this hole, light leakage to an outside is generated, so that lowering of a shielding property and lowering of dust-proof property are subjects to be challenged. The optical connector plug of the invention is proposed for solving the above-described problems.